Allow all entries to be searched when limiting entry sources for entry fields

[jsunsawyer]

Description

Currently, you can only search all entries when adding an entry to an entries field when All sources are available. As soon as you limit the available sources, you can only select and search within each of the limited sources.

We need to be able to limit entry sources to prevent users from selecting entries that are used for relational data and don't have public URLs. We'd like to do this without making it more difficult to quickly find and add a desired entry.

Ideally, you'd still be able to search from all of the limited number of sources.

Steps to reproduce

1. Create an entry field with a few sources available. (Not all)
2. Add field to a section.
3. Add an entry to the field and attempt to search.
4. Compare to entry field with all sources available.

Additional info

• Craft version: 3.0.4